1. Field of the Invention
The present invention relates to a switchable antenna, and more particularly, to a switchable antenna able to reduce interference, eliminate dead zones, and switch between an omnidirectional mode and a directional mode.
2. Description of the Prior Art
Antennas are utilized to emit and receive radio-frequency waves, thereby transmitting or exchanging radio-frequency signals. Basically, antennas can be divided into omnidirectional antennas and directional antennas according to radiation patterns. Omnidirectional antennas do not need to be pointed and provide equal coverage in all directions. Directional antennas point energy toward a specific direction for concentration within a targeted area, and hence are ideal to increase transmission efficiency covering specific area.
In general, directivity of an antenna is determined after the antenna has been designed. However, it is preferable to operate an antenna in different modes. Namely, it is a common goal in the industry to efficiently switch an electronic product between an omnidirectional mode and a directional mode.